Our laboratory is continuing studies on structure-function relationships of human hemoglobins. During the past year we have focused on: 1) Functional properties of Hb Cranston; 2) The presence of F cells in a clonal hematopoietic disorder; 3) The assembly of alpha and beta chains to form normal and variant hemoglobins; 4) Studies of Hb D-Los Angeles and Hb Aida occurring in the same patient. During the forthcoming year we will focus on: 1) Kinetics of assembly of hemoglobin subunits. 2) The polymerization of heme-substituted Hbs.